With rapid spreading of word processors or personal computers, various recording systems have been adopted. As one of the recording systems, an ink-jet recording system is known.
The ink-jet recording system is a recording system wherein ink droplets are jetted onto a surface of a recording medium and attached thereon. Therefore, the surface of the recording medium needs to rapidly absorb the jetted ink droplets. The recording media for use in the ink-jet recording system are not limited to paper but include various materials such as transparent resin films for OHP and metals. Some of these recording media have no hydrophilic surfaces. Therefore, in order to clearly record information, an ink-receiving layer needs to be provided on a surface of a substrate constituting the recording medium.
On that account, there have been made a great number of proposals for forming an ink-receiving layer (recording layer) containing hydrophilic resins, such as starch, water-soluble cellulose derivative, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone and polyvinyl acetal, on the substrate surface (see: Japanese Patent Laid-Open Publications No. 174381/1984, No. 132785/1985, No. 145879/1985, No. 224578/1985, No. 32788/1986, No. 169176/1996 and No. 174994/1996).
The ink-jet recording media are required to have the following characteristics: (1) permeation of ink inside the ink-receiving layer must be rapidly made, color running should not take place, and clear color having high chromaticity can be reproduced; (2) in the multi-color recording using a combination of ink components, each ink component must be rapidly absorbed even if ink dots are superposed on the same surface of the recording medium, and in the high-speed recording, the recorded surface must be free from staining, and the ink absorption rate and the ink absorption quantity must be both satisfactory; (3) the recording medium must have water resistance, and even if the recorded image is contacted by water, running or bleeding of ink of the image must not take place; (4) even if the ink-jet recording media are stored in the superposed state, they must be free from blocking; and (5) even if the printed matter is stored for a long period of time, color fading or the like should not take place.
In the ink-jet recording media disclosed in the above publications, however, there is almost no medium satisfying all of the above-mentioned characteristics required for ink-jet recording media.
For example, the hydrophilic resins used in the ink-receiving layer have problems in that they do not have sufficient water resistance because they have a polar group to ensure the hydrophilic properties and that the color of the ink attached to the ink-receiving layer sometimes changes because of the polar group introduced to ensure the hydrophilic properties.
It is an object of the invention to provide a novel acrylic copolymer, acrylic resin particles and uses thereof.
More particularly, the object of the invention is to provide a novel acrylic copolymer containing recurring units derived from a specific monomer having an ethylenic double bond and a polar group, acrylic resin particles obtained by shaping the acrylic copolymer into particles, and an ink-jet recording medium of good image-forming properties using the acrylic resin particles.